The present invention relates to a grouting composition.
Anchor bolts are employed in various fields of engineering, for example, as strengthening or reinforcing members in rock formations and in structural bodies. The bolts are inserted into drill holes in the formation or body, and often are fixed or anchored, at their inner end or over substantially their entire length, by means of a reactive grouting composition which hardens around the bolt. When used in a mine roof, bolts grouted in this manner help significantly to prevent mine roof failure. Because unsupported rock strata have a tendency to move vertically and laterally, and this motion can cause the roof to fall, it is important that bolts be installed as soon as possible in a newly exposed roof and that the required strength provided by the hardening of the grouting composition be developed rapidly, e.g., in a matter of minutes, or within an hour or so, depending on the type of mine. Rapid hardening also contributes to the efficiency of the bolt installing operation.
A grouting composition generally contains a resin and water. Such a water-based composition is typically placed in boltholes using tubular compartmented cartridges and held rigid by an internal package pressure. The internal pressure is created by a cartridging machine when end clips are applied to the cartridge film to seal the contents. Water as a carrier in such systems results in a product with better shelf life than similar compositions containing oil-based carriers. However, water loss can occur with extended storage of the above components. Any loss of water from the cartridges, either by diffusion through the plastic or by leakage from the end clips, will cause loss of internal pressure. Without internal pressure the cartridges are limp, and when picked up at the center will sag greatly This limpness makes them very difficult to insert in close-fitting overhead boltholes. When enough water loss has occurred, the cartridges are too limp to be installed in the bolthole and must be destroyed. Since the polyester resin film has an appreciable water diffusion rate, some cartridge limpness may occur after about 2 months storage, and often unacceptable limpness may occur after 6 months storage.
Therefore, there is an increasing need to develop a water-based composition that can be used as grouting composition which can gel in a desired time and has a reduced water loss or an increased bonding strength.
According to the present invention, a composition which can be used as a grouting composition is provided. The composition comprises, consists essentially of, or consists of a first component and a second component in which the first component comprises a peroxide, a liquid which comprises water, a sugar, and a solid particulate; and the second component comprises a polymer, a crosslinking agent, and a solid particulate.
Suitable peroxide can be an organic peroxide, an inorganic peroxide, or combinations thereof The presently preferred peroxide is an organic peroxide which can be any diacyl peroxides. Examples of suitable organic peroxides include, but are not limited to, benzoyl peroxide, dichlorobenzoyl peroxide, dibromobenzoyl peroxide, dimethoxy benzoyl peroxide, and combinations of two or more thereof The presently preferred organic peroxide is benzoyl peroxide because it is readily available and effective for use in a grouting composition.
Any liquid that comprises water can be used in the composition of the first embodiment of the invention. The liquid can also comprise a second liquid such as a freezing point depressing material. The second liquid can be a polyalcohol such as ethylene glycol and propylene glycol, solution of calcium chloride, solution of sodium chloride, and combinations of two or more thereof.
A suitable liquid can also comprise a thickener which keeps the liquid in diffused or well-mingled form. Examples of suitable thickeners include, but are not limited to, cellulose, methyl cellulose, hydroxyethyl cellulose, and combinations of two or more thereof A thickener can be present in the first component in any quantity that can thicken the liquid, generally in the range of from about 0.1 to about 30 weight %, based on the total weight of the liquid.
According to the invention, the term xe2x80x9csugarxe2x80x9d refers to a carbohydrate selected from the group consisting of monosaccharide, disaccharide, trisaccharide, oligosaccharide having about 4 to about 25, preferably 4 to 20, repeat units per molecule, sugar alcohol, derivative thereof, and combinations of two or more thereof Generally a sugar employed herein is substantially soluble in water and does not substantially crystallize in water at ambient temperature. A sugar alcohol includes sugars having their carbonyl group converted to alcohol group such as sorbitol and mannitol. A sugar can also include one having one or more hydroxyl groups that have been alkylated such as, for example, methyl glyosides; having amino group such as, for example, glucosamine, galactasamine; in lactone forms such as, for example, gluconolactone, glucuronolactone, ascorbic acid, dehydroascorbic acid; containing one or more carboxyl groups such as N-acetyl muranic acid; and combinations of two or more thereof.
Specific examples of suitable sugars include, but are not limited to, glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribulose, xylulose, psicose, fructose, sorbose, tagatose, sorbitol, mannitol, inasitol, gluonic acid, glucaric acid, gluconolactone, ascorbic acid, gluosamine, galactosamine, lactose, sucrose, rafinoise, melezitose, stachyose maltose, corn syrup, molasses, and combinations of two or more thereof The presently preferred sugars are corn syrup, sucrose, and molasses for they are inexpensive and readily available.
All sugars illustrated above can be either D or L configuration and can be either xcex1 or xcex2 stereoisomer.
A solid particulate is often served as filler in the composition of the invention to provide the interfacial strength and the desired rheological properties of the composition. The term xe2x80x9csolid particulatexe2x80x9d is interchangeable with the term xe2x80x9cfillerxe2x80x9d. Any solid particulate material that is substantially inert toward water and toward the materials in the composition into which it is to be incorporated can be used. Examples of suitable solid particulate include, but are not limited to, limestone (calcium carbonate), sand, cement, gypsum, gypsum plaster, fiber glass, paper fiber, and combinations of two or more thereof. Limestone and sand are preferred fillers, limestone being especially preferred because of pumping and cost considerations. Other solid particulate materials can be used, such as those described in U.S. Pat. No. 4,280,943, disclosure of which is herein incorporated by reference. Different particle sizes and shapes can be used, as can combinations of different fillers.
For maximum shelf life of a grouting composition disclosed in the invention, it is desirable that the solid particulate used be low in iron content (preferably below 0.001% by weight). If a filler which does contain any appreciable amounts of iron such as, for example, 0.001% or more by weight, it is preferable that sugar not be an aliphatic monosaccharide sugar having a carboxyl group. Preferably, when an iron-containing filler such as limestone is used as the particulate solid, the sugar used is selected from the group of disaccharides, sugar alcohols such as sorbitol, and oligosaccharides.
Peroxide can be present in the first component in any quantity as long as an effective grouting composition can be produced. Presently it is preferred that the peroxide be present in the first component in the range of from about 0.5 to about 10 weight percent (%), preferably about 1 to about 4%, and most preferably 1.5 to 2%.
The weight percent of the liquid in the first component of the invention composition can be any % as long as the percentage can provide a stabilized grouting composition. Generally, the weight % of liquid can be in the range of from about 5 to about 35%, preferably about 10 to about 30%, and most preferably 15 to 25%, based on the total weight of the first component.
The water content in the liquid can be in the range of from about 10 to about 100, preferably about 30 to about 75, and most preferably 40 to 70 weight %, based on the total weight of the liquid component. The second liquid, if present, makes up the rest of the liquid.
According to the present invention, the sugar can be present in the first component in any quantity so long as the quantity can provide a stabilized grouting composition. Generally the weight % of sugar in the first component can be in the range of from about 1 to about 30%, preferably about 2 to about 20%, and most preferably 5 to 10%.
Similarly, the solid particulate can be present in the first component in such an amount that can produce a stabilized grouting composition. The weight % of the solid particulate can be in the range of from about 50 to about 90%, preferably about 70 to about 85%, and most preferably 75 to 80%.
According to the invention, the second component comprises a polymerizable polymer. The polymerizable polymer, for example, can be the polymerized product of a polyalcohol and an ethylenically unsaturated polycarboxylic acid or acid anhydride. Examples of such acids or acid anhydrides, include, but are not limited to, nialeic acid, fumaric acid, maleic anhydride, phthalic anhydride, and combinations of two or more thereof An aliphatic polyalcohol can be ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 2-methyl-2,3-propanediol, or any dihydroxy compound that can be esterified with a carboxylic acid. Ethylene glycol or propylene glycol is preferred polyalcohol. Examples of presently preferred polymers include, but are not limited to, polymers having repeat units derived from (1) ethylene glycol, propylene glycol, diethylene glycol, or combinations of two or more thereof and (2) maleic anhydride, phthalic acid, or combinations thereof because of cost and stability over a wide temperature range for up to one year, low toxic properties, and relatively high flash point.
The polymer can be present in the second component in a quantity such that a grouting composition can be produced. Generally, the weight % of the polymer in the second component can be in the range of from about 5 to about 40%, preferably about 7 to about 30%, and most preferably 10 to 20%.
According to the invention, any crosslinking agent which can crosslink with a polymer disclosed above can be used. Examples of suitable crosslinking agents include, but are not limited to, styrene, vinyl toluene, ethylene, propylene, butene, pentene, hexene, acrylate, methacrylate, N,N-dimethylacrylate, and combinations of two or more thereof The presently preferred crosslinking agent is styrene because it is effective and readily available.
The quantity of the crosslinking agent required is the quantity that can produce a grouting composition having a reasonable gelling time and gel strength. Therefore, the crosslinking agent can be present in the second component in any quantity that can produce such grouting composition. The weight % of the crosslinking agent in the second component can be in the range of from about 1 to about 10%, preferably about 3 to about 7%.
The solid particulate, as disclosed above in the first embodiment of the invention, can be present in the second component in such an amount that can produce a stabilized grouting composition. The weight % of the solid particulate can be in the range of from about 50 to about 90%, preferably about 70 to about 85%, and most preferably 75 to 80%.
The second component can also comprise a promoter which can produce a sufficiently strong and stable grouting composition. The presently preferred promoter is an amine such as, for example, aniline, dimethyl aniline, diehtyl aniline, dipropyl aniline, dimethyl p-toluidine, or combinations of two or more thereof or a phenolic compound such as, for example, hydroquinone, hydroxy benzoic acids, or combinations of two or more thereof.
The promoter can be present in the second component in an amount that can produce a sufficiently strong and stable grouting composition. Generally, the amount can be in the range of from about 0.01 to about 5, preferably about 0.1 to about 3, more preferably about 0.15 to about 5, and most preferably 0.3 to 1 weight %, based on the total weight of the second component.
The second component can further comprise a sugar, a liquid, a stabilizer, or combinations of two or more thereof The definitions and examples of sugar, and liquid are the same as those disclosed above. The quantities of sugar, promoter, and liquid in the second component can also be the same as those disclosed above for the first component. A stabilizer such as a phenolic compound can be used in the composition in the range of from about 0.0001 to about 5 weight %. Specific examples of stabilizers include, but are not limited to, hydroquinone, p-hydroxybenzoic acid, aminophenol, and combinations of two or more thereof.
The first and second components can be produced by combining individual components using any suitable means known to one skilled in the art such as, for example, blending, mixing, or kneading. A grouting composition can be produced by combining the first and second components by the means disclosed in U.S. Pat. No. 4,280,943, disclosure of which is herein incorporated by reference.
Generally, the weight ratio of the first component to the second component can be in the range of from about 0.1:1 to about 10:1, preferably 1:1 to 1:5.
The composition of the present invention can be used for anchoring a strengthening or reinforcing member in a hole.
The present invention further provides a process which can be used to prevent, reduce, or control fluid loss in a grouting composition. The process comprises combining the composition with a sugar in which the composition comprises a first component and a second component. The first component comprises a peroxide, a liquid which comprises water, and a solid particulate. The second component comprises a polymer and a crosslinking agent. The definition, scope, and quantity of sugar, peroxide, liquid, solid particulate, polymer, and crosslinking agent are the same as those disclosed above.